Annual report pursuant to Section 13 and 15(d)

Goodwill and Intangible Assets, Net of Accumulated Amortization (Details Textual)

v2.4.0.8
Goodwill and Intangible Assets, Net of Accumulated Amortization (Details Textual) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
May 31, 2014
May 31, 2013
May 31, 2012
Goodwill and Intangible Assets, Net of Accumulated Amortization (Textual)      
Goodwill $ 540.3 $ 533.9  
Amortization expense relating to intangible assets $ 15.9 $ 19.0 $ 23.0
Finite-Lived Intangible Assets [Line Items]      
Acquired intangible assets, Weighted average amortization period 7 years 3 months 19 days    
Customer Lists [Member]
      
Finite-Lived Intangible Assets [Line Items]      
Acquired intangible assets, Weighted average amortization period 7 years 4 months 24 days    
Other Intangible Assets [Member]
      
Finite-Lived Intangible Assets [Line Items]      
Acquired intangible assets, Weighted average amortization period 3 years